If your interest in a FREE navigation program, (I'm always interested in free stuff that works), you can' really beat SeaClear. http://www.sping.com/seaclear/ All you need is a laptop, a GPS receiver, (you can by a bluetooth one for less than $100), and some downloaded charts. You can used the government free US BSB charts, or scan your own, create a datum and your ready to roll. Unfortunately I don't believe the Government vector charts will work. (This is more of a shortcoming to me than it would be to most people. I have this thing about vector charts.) To be honest, I have only really tested once on the water. It's quite easy to load the charts and form chart groups, and then pic the approprate chart for your location. I plan on making more use of it this season and will report back on my progress.